Technical Field
[0001] The present invention relates to a cross-flow fan and an air conditioner using the
cross-flow fan.
Background Art
[0002] In Patent Literature 1, there is disclosed a transverse fan including blades, each
being inclined at a predetermined angle with respect to a fan axis and being mounted
with unequally set mounting pitches. Further, in the transverse fan, each blade is
thin in an impeller longitudinal direction.
[0003] In Patent Literature 2, there is disclosed an axial fan including blades each formed
so that a blade cross section orthogonal to a rotational axis decreases in size as
approaching from a base portion to a distal end portion of each of the blade portions
arranged side by side on a main surface. Further, in the axial fan, a center of the
blade cross section orthogonal to the rotational axis is displaced frontward or backward
in a direction of rotation about the rotational axis as approaching from the base
portion of the blade portion toward the tip portion of the blade portion. Further,
the blade cross section is curved radially outward.
[0004] Further, in Patent Literature 3, there is disclosed a fan including first components
in each of which a tip portion of a blade is inclined in a rotational direction from
a base of the blade, and second components in each of which the tip portion of the
blade is inclined in a counter-rotational direction from the base of the blade. The
first components and the second components are alternately stacked.
Citation List
Patent Literature
Summary of Invention
Technical Problem
[0006] However, as for the space between a pair of rings, the cross-flow fan tends to blow
out relatively a large amount of flow from the vicinity of the center between the
pair of rings, which is located away from the pair of rings, thus causing a problem
of a non-uniform flow between the pair of rings. Further, the above-mentioned related-art
fans disclosed in Patent Literature 1 to Patent Literature 3 can generate flow components
directed from one ring toward the other ring but have difficulty in alleviating the
above-mentioned problem of the non-uniform flow between the pair of rings.
[0007] The present invention has been made in view of the above, and an object of the present
invention is to provide a cross-flow fan capable of alleviating a non-uniform flow
between a pair of support plates.
Solution to Problem
[0008] In order to attain the above-mentioned object, the present invention provides a cross-flow
fan as set forth in claim 1. Further, in order to attain the above-mentioned object,
according to one embodiment of the present invention, there is provided an air conditioner,
including: a stabilizer configured to partition an inlet-side air duct and an outlet-side
air duct inside a main body; a cross-flow fan arranged between the inlet-side air
duct and the outlet-side air duct; a ventilation resistor arranged inside the main
body; and a guide wall configured to guide air discharged from the cross-flow fan
to an air outlet of the main body, the cross-flow fan being the above-mentioned cross-flow
fan according to the one embodiment of the present invention.
Advantageous Effects of Invention
[0009] According to the one embodiment of the present invention, it is possible to alleviate
the non-uniform flow between the pair of support plates.
Brief Description of Drawings
[0010]
FIG. 1 is a view for illustrating an installing state of an air conditioner according
to a first embodiment of the present invention when viewed from the interior of a
room.
FIG. 2 is a vertical sectional view of the air conditioner of FIG. 1.
FIG. 3 is a view for illustrating a front side and a lateral side of an impeller of
a cross-flow fan to be mounted on the air conditioner of FIG. 1.
FIG. 4 is a perspective view of a single blade of the impeller of the cross-flow fan
when viewed from a surface on an impeller rotational direction side (blade pressure
surface).
FIG. 5 is a view for illustrating a blade lateral shape taken along the line A-A in
FIG. 3 and a blade lateral shape taken along the line B-B in FIG. 3.
FIG. 6 is a cross-sectional view of a blade of the cross-flow fan at a center portion
between a pair of rings in a rotational axis direction.
FIG. 7 is a cross-sectional view of the blade of the cross-flow fan at the center
portion between the pair of rings in the rotational axis direction.
FIG. 8 is a cross-sectional view of the blade of the cross-flow fan at the center
portion between the pair of rings in the rotational axis direction.
FIG. 9 is a view for illustrating a second embodiment of the present invention in
the same manner as in FIG. 3.
FIG. 10 is a view for illustrating the second embodiment of the present invention
in the same manner as in FIG. 5.
FIG. 11 is a view for illustrating a third embodiment of the present invention in
the same manner as in FIG. 3.
FIG. 12 is a view for illustrating the third embodiment of the present invention in
the same manner as in FIG. 4.
FIG. 13 is a view for illustrating the third embodiment of the present invention in
the same manner as in FIG. 5.
FIG. 14 is a view for illustrating a fourth embodiment of the present invention in
the same manner as in FIG. 4.
Description of Embodiments
[0011] Now, an air conditioner according to embodiments of the present invention is described
with reference to the accompanying drawings. Note that, in the drawings, the same
reference symbols represent the same or corresponding parts.
First Embodiment
[0012] FIG. 1 is an installation schematic view of an air conditioner having a cross-flow
fan mounted thereon according to a first embodiment of the present invention when
viewed from a room. FIG. 2 is a vertical sectional view of the air conditioner of
FIG. 1. FIG. 3 is a view for illustrating a front side and a lateral side of an impeller
of the cross-flow fan to be mounted on the air conditioner of FIG. 1.
[0013] As illustrated in FIG. 1, an air conditioner (indoor unit) 100 includes a main body
1 and a front panel 1b installed on the front side of the main body 1, which form
an outer shape of the air conditioner 100. In this case, in FIG. 1, the air conditioner
100 is installed on a wall 11a of a room 11 that is a space to be air-conditioned.
That is, FIG. 1 is an illustration of the air conditioner 100 of a wall-mounting type
as an example, but the present invention is not limited to this mode. For example,
a ceiling concealed type may be employed. Further, the air conditioner 100 is not
limited to be installed in the room 11, and may be installed in a room of a building
or a storehouse, for example.
[0014] As illustrated in FIG. 2, in a main body upper portion 1a forming the upper portion
of the main body 1, a suction grille 2 configured to suck air inside the room into
the air conditioner 100 is formed. On the lower side of the main body 1, an air outlet
3 configured to supply the conditioned air into the room is formed, and further a
guide wall 10 configured to guide the air discharged from a cross-flow fan 8 described
later to the air outlet 3 is formed.
[0015] As illustrated in FIG. 2, the main body 1 includes a filter (ventilation resistor)
5 configured to remove dust and the like in the air sucked through the suction grille
2, a heat exchanger (ventilation resistor) 7 configured to generate conditioned air
by transferring hot or cold energy of refrigerant to air, a stabilizer 9 configured
to partition an inlet-side air duct E1 and an outlet-side air duct E2, the cross-flow
fan 8, which is arranged between the inlet-side air duct E1 and the outlet-side air
duct E2, and is configured to suck air through the suction grille 2 and blow out air
through the air outlet 3, and a vertical airflow-direction vane 4a and a lateral airflow-direction
vane 4b configured to adjust the direction of the air blown out from the cross-flow
fan 8.
[0016] The suction grille 2 is an opening through which the air inside the room is forcibly
introduced into the air conditioner 100 by the cross-flow fan 8. The suction grille
2 is formed as an opening in the upper surface of the main body 1. The air outlet
3 is an opening through which air, which has been sucked through the suction grille
2 and passed through the heat exchanger 7, passes when the air is supplied into the
room. The air outlet 3 is formed as an opening in the front panel 1b. The guide wall
10 forms the outlet-side air duct E2 in cooperation with the lower surface side of
the stabilizer 9. The guide wall 10 forms a helical surface from the cross-flow fan
8 toward the air outlet 3.
[0017] The filter 5 is formed into, for example, a mesh shape, and is configured to remove
dust and the like in the air sucked through the suction grille 2. The filter 5 is
mounted on the downstream side of the suction grille 2 and on the upstream side of
the heat exchanger 7 in the air duct from the suction grille 2 to the air outlet 3
(center portion inside the main body 1).
[0018] The heat exchanger 7 (indoor heat exchanger) functions as an evaporator to cool the
air during cooling operation, and functions as a condenser (radiator) to heat the
air during heating operation. The heat exchanger 7 is mounted on the downstream side
of the filter 5 and on the upstream side of the cross-flow fan 8 in the air duct from
the suction grille 2 to the air outlet 3 (center portion inside the main body 1).
Note that, in FIG. 2, the heat exchanger 7 is shaped so as to surround the front side
and the upper side of the cross-flow fan 8. However, this shape is merely an example,
and the present invention is not limited thereto.
[0019] The heat exchanger 7 is connected to an outdoor unit of a known mode including a
compressor, an outdoor heat exchanger, an expansion device, and the like, to thereby
construct a refrigeration cycle. Further, as the heat exchanger 7, for example, a
cross-fin type fin-and-tube heat exchanger including a heat transfer tube and a large
number of fins is used.
[0020] The stabilizer 9 is configured to partition the inlet-side air duct E1 and the outlet-side
air duct E2, and as illustrated in FIG. 2, the stabilizer 9 is mounted on the lower
side of the heat exchanger 7. The inlet-side air duct E1 is positioned on the upper
surface side of the stabilizer 9, and the outlet-side air duct E2 is positioned on
the lower surface side of the stabilizer 9. The stabilizer 9 includes a drain pan
6 configured to temporarily accumulate dew condensation water adhering on the heat
exchanger 7.
[0021] The cross-flow fan 8 is configured to suck air inside the room through the suction
grille 2 and blow out conditioned air through the air outlet 3. The cross-flow fan
8 is mounted on the downstream side of the heat exchanger 7 and on the upstream side
of the air outlet 3 in the air duct from the suction grille 2 to the air outlet 3
(center portion inside the main body 1).
[0022] The cross-flow fan 8 includes, as illustrated in FIG. 3, an impeller 8a made of a
thermoplastic resin such as an AS resin (styrene-acrylonitrile copolymer) with glass
fibers, a motor 12 configured to rotate the impeller 8a, and a motor shaft 12a configured
to transmit the rotation of the motor 12 to the impeller 8a. The impeller 8a itself
rotates to suck the air inside the room through the suction grille 2 and send the
conditioned air to the air outlet 3.
[0023] The impeller 8a is formed by coupling a plurality of impeller elements 8d to each
other, and each of the impeller elements 8d includes a plurality of blades 8c and
at least one ring (support plate) 8b fixed to the end portion side of the plurality
of blades 8c. That is, in the impeller element 8d, each of the plurality of blades
8c extends from a side surface of an outer peripheral portion of the disc-shaped ring
8b so as to be substantially perpendicular to the side surface. In addition, the plurality
of blades 8c are arrayed at predetermined intervals in the circumferential direction
of the ring 8b. The impeller 8a is integrated by welding and coupling the plurality
of impeller elements 8d to each other as described above.
[0024] The impeller 8a includes a fan boss 8e protruding on the inner (center) side of the
impeller 8a. The fan boss 8e is fixed to the motor shaft 12a with a screw or the like.
Further, in the impeller 8a, one side of the impeller 8a is supported by the motor
shaft 12a via the fan boss 8e, and the other side of the impeller 8a is supported
by a fan shaft 8f. With this, the impeller 8a rotates in a rotational direction RO
about an impeller rotation center O of the impeller 8a under a state in which both
end sides thereof are supported, which enables sucking of the air inside the room
through the suction grille 2 and sending of the conditioned air through the air outlet
3. Note that, the impeller 8a is described in detail later.
[0025] The vertical airflow-direction vane 4a is configured to vertically adjust the direction
of the air blown out from the cross-flow fan 8, and the lateral airflow-direction
vane 4b is configured to laterally adjust the direction of the air blown out from
the cross-flow fan 8. The vertical airflow-direction vane 4a is mounted on the downstream
side with respect to the lateral airflow-direction vane 4b. Note that, the vertical
direction herein corresponds to the vertical direction of FIG. 2, and the lateral
direction herein corresponds to a front-back direction of the drawing sheet of FIG.
2.
[0026] FIG. 4 is a perspective view of a single blade of the impeller of the cross-flow
fan when viewed from a surface on an impeller rotational direction side (blade pressure
surface). FIG. 5 is a view for illustrating a blade lateral shape taken along the
line A-A in FIG. 3 and a blade lateral shape taken along the line B-B in FIG. 3.
[0027] As illustrated in FIG. 4 and FIG. 5, each of the plurality of blades 8c is constructed
to have such a shape that an inner peripheral end portion 15b is advanced again in
the rotational direction after being retreated in the rotational direction from one
corresponding ring toward the other corresponding ring, and an outer peripheral end
portion 15a is also advanced again in the rotational direction after being retreated
in the rotational direction from one corresponding ring toward the other corresponding
ring. In other words, as illustrated in FIG. 3 and FIG. 4, when the pressure surface
of the blade 8c is viewed in a projective manner, the inner peripheral end portion
15b and the outer peripheral end portion 15a in each of the plurality of blades 8c
have inverted V-shapes, respectively. Therefore, each of the inner peripheral end
portion 15b and the outer peripheral end portion 15a is retreated most in the rotational
direction at the center portion between a pair of rings in a rotational axis direction
and is advanced more in the rotational direction at portions on both sides of the
center portion as approaching to the rings. Further, as illustrated in FIG. 5, the
blade 8c has a constant cross section (cross section in a direction orthogonal to
the rotational axis) over the rotational axis direction, but the center portion in
the rotational axis direction is displaced from portions facing the rings by an angle
δ.
[0028] Further, in each of the plurality of blades 8c, as illustrated in FIG. 5, the blade
outer diameter (distance between the outer peripheral end portion 15a to be described
later and the rotational axis O) and the blade outer diameter (distance between the
inner peripheral end portion 15b to be described later and the rotational axis O)
are kept the same over the rotational axis direction. Further, the cross-sectional
area shapes of the blades 8c are also kept the same over the rotational axis direction.
In other words, each of the plurality of blades 8c is formed into such a three-dimensional
shape as to advance or retreat in the impeller rotational direction while keeping
the same blade cross section orthogonal to the impeller rotational axis.
[0029] Next, the cross-sectional shape of the blade 8c in the direction orthogonal to the
rotational axis is described in detail. FIG. 6 to FIG. 8 are cross-sectional views
of the blade of the cross-flow fan at the center portion between the pair of rings
in the rotational axis direction.
[0030] As illustrated in FIG. 6 to FIG. 8, the outer peripheral end portion 15a and the
inner peripheral end portion 15b of the blade 8c are each formed into an arc shape.
Further, the blade 8c is formed so that the outer peripheral end portion 15a side
is inclined forward in the impeller rotational direction RO with respect to the inner
peripheral end portion 15b side. That is, when the blade 8c is viewed in the vertical
cross section, a blade pressure surface 13a and a blade suction surface 13b of the
blade 8c are curved in the impeller rotational direction RO as approaching from the
impeller rotation center (rotational axis) O of the impeller 8a toward the outer side
of the blade 8c.
[0031] A center of a circle corresponding to the arc shape formed in the outer peripheral
end portion 15a is represented by P1 (also referredto as "arc center P1"), and acenterof
acircle corresponding to the arc shape formed in the inner peripheral end portion
15b is represented by P2 (also referred to as "arc center P2"). Further, when a line
segment connecting together the arc centers P1 and P2 is represented by a blade chord
line (blade chord) L, as illustrated in FIG. 8, the length of the blade chord line
L is set to Lo (hereinafter also referred to as "blade chord length Lo").
[0032] The blade 8c includes the blade pressure surface 13a, which is a surface on the rotational
direction RO side of the impeller 8a, and the blade suction surface 13b, which is
a surface on an opposite side to the rotational direction RO side of the impeller
8a. In the vicinity of the center of the blade chord line L, the blade 8c has a concave
shape curved in a direction from the blade pressure surface 13a toward the blade suction
surface 13b.
[0033] Further, in the blade 8c, a radius of a circle corresponding to the arc shape on
the blade pressure surface 13a side is different between the outer peripheral side
of the impeller 8a and the inner peripheral side of the impeller 8a. That is, as illustrated
in FIG. 7, the surface of the blade 8c on the blade pressure surface 13a side is a
multiple-arc curved surface and includes an outer peripheral curved surface Bp1 in
which a radius (arc radius) corresponding to the arc shape on the outer peripheral
side of the impeller 8a is Rp1, and an inner peripheral curved surface Bp2 in which
a radius (arc radius) corresponding to the arc shape on the inner peripheral side
of the impeller 8a is Rp2. Further, the surface of the blade 8c on the blade pressure
surface 13a side includes a flat surface Qp having a planar shape, which is connected
to an inner peripheral end portion of the end portions of the inner peripheral curved
surface Bp2.
[0034] As described above, the surface of the blade 8c on the blade pressure surface 13a
side is formed in a manner that the outer peripheral curved surface Bp1, the inner
peripheral curved surface Bp2, and the flat surface Qp are continuously connected
to one another. Note that, when the blade 8c is viewed in the vertical cross section,
the straight line forming the flat surface Qp is a tangent at a point connected to
the arc forming the inner peripheral curved surface Bp2.
[0035] On the other hand, the surface of the blade 8c on the blade suction surface 13b side
is a surface corresponding to the surface on the blade pressure surface 13a side.
Specifically, the surface of the blade 8c on the blade suction surface 13b side includes
an outer peripheral curved surface Bs1 in which a radius (arc radius) corresponding
to the arc shape on the outer peripheral side of the impeller 8a is Rs1, and an inner
peripheral curved surface Bs2 in which a radius (arc radius) corresponding to the
arc shape on the inner peripheral side of the impeller 8a is Rs2. Further, the surface
of the blade 8c on the blade suction surface 13b side includes a flat surface Qs having
a planar shape, which is connected to an inner peripheral end portion of the end portions
of the inner peripheral curved surface Bs2.
[0036] As described above, the surface of the blade 8c on the blade suction surface 13b
side is formed in a manner that the outer peripheral curved surface Bs1, the inner
peripheral curved surface Bs2, and the flat surface Qs are continuously connected
to one another. Note that, when the blade 8c is viewed in the vertical cross section,
the straight line forming the flat surface Qs is a tangent at a point connected to
the arc forming the inner peripheral curved surface Bs2.
[0037] Next, the blade thickness is described. When the blade 8c is viewed in the vertical
cross section, and when a diameter of a circle inscribed in the blade surfaces is
represented by a blade thickness (thickness) t, as illustrated in FIG. 7, a blade
thickness (thickness) t1 at the outer peripheral end portion 15a is smaller than a
blade thickness (thickness) t2 at the inner peripheral end portion 15b. Note that,
the blade thickness t1 corresponds to 2 × radius R1 of the circle forming the arc
of the outer peripheral end portion 15a, and the blade thickness t2 corresponds to
2 × radius R2 of the circle forming the arc of the inner peripheral end portion 15b.
[0038] In other words, when the diameter of the circle inscribed in the blade pressure surface
13a and the blade suction surface 13b of the blade 8c represents the blade thickness,
the blade thickness is formed as follows. The blade thickness of the outer peripheral
end portion 15a is smaller than that of the inner peripheral end portion 15b, and
the blade thickness gradually increases as approaching from the outer peripheral end
portion 15a toward the center to become maximum at a predetermined position in the
vicinity of the center. Then, the blade thickness gradually decreases as approaching
toward the inner side to become substantially the same thickness at a straight portion
Q.
[0039] More specifically, in a range of the outer peripheral curved surface Bp1, the inner
peripheral curved surface Bp2, the outer peripheral curved surface Bs1, and the inner
peripheral curved surface Bs2 formed in the blade pressure surface 13a and the blade
suction surface 13b excluding the outer peripheral end portion 15a and the inner peripheral
end portion 15b, the blade thickness t of the blade 8c gradually increases as approaching
from the outer peripheral end portion 15a toward the center of the blade 8c, becomes
a maximum thickness t3 at the predetermined position in the vicinity of the center
of the blade chord line L, and gradually decreases as approaching toward the inner
peripheral end portion 15b. Then, in a range of the straight portion Q, that is, in
a range between the flat surface Qp and the flat surface Qs, the blade thickness t
is the inner peripheral end portion thickness t2 that is a substantially constant
value.
[0040] In this case, a part of the blade 8c having the flat surfaces Qp and Qs of the inner
peripheral end portion 15b as surfaces is referred to as the straight portion Q. That
is, the blade suction surface 13b of the blade 8c is formed of the multiple arcs and
the straight portion Q in a range from the outer peripheral side toward the inner
peripheral side of the impeller.
[0041] The cross-flow fan having the above-mentioned configuration and the air conditioner
having the cross-flow fan mounted thereon can achieve the following effects.
[0042] First, in the case where air is sucked to the inside from the outside of the cross-flow
fan 8 (that is, in the case of a flow in the cross-flow fan 8 at the blades 8c that
are located at an upper left position in the drawing sheet in FIG. 2, in other words,
in the case of a flow at the blades 8c that are positioned on the inlet-side air duct
E1 side), the air flows along each of the plurality of blades 8c from the outer peripheral
end portion 15a toward the inner peripheral end portion 15b as indicated by the dotted
arrows in FIG. 4. Therefore, the air flowing out from the inner peripheral end portion
15b toward the inside of the cross-flow fan 8 flows so as to diffuse toward a corresponding
pair of rings 8b. Accordingly, as for the space between the pair of rings, in the
cross-flow fan that tends to blow out relatively a large amount of flow from the vicinity
of the center between the pair of rings, which is located away from the pair of rings,
the flow can also be positively distributed to the vicinities of the pair of rings
to achieve a uniform flow between the pair of rings.
[0043] On the other hand, in the case where air is blown out to the outside from the inside
of the cross-flow fan 8 (that is, in the case of a flow in the cross-flow fan 8 at
the blades 8c that are located at a lower right position in the drawing sheet in FIG.
2, in other words, in the case of a flow at the blades 8c that are positioned on the
outlet-side air duct E2 side), the air flows from the inner peripheral end portion
15b toward the outer peripheral end portion 15a as indicated by the solid arrows in
FIG. 4. Therefore, when flowing over the inner peripheral end portion 15b, the air
is accompanied by a blade tip vortex with the inner peripheral end portion 15b as
an end portion and flows along the blade 8c as a flow with suppressed separation.
Such suppressed separation allows a uniform flow to be maintained in a promotive manner.
[0044] In addition, the following functions and effects can be obtained.
- (1) The suction surface 13b of the blade 8c is formed of the multiple arcs and the
straight portion Q in the range from the outer peripheral side toward the inner peripheral
side of the impeller. Thus, when the blade 8c passes through the inlet-side air duct
E1, the flow on the blade surface that is about to separate at the outer peripheral
curved surface Bs1 reattaches onto the following inner peripheral curved surface Bs2
having a different arc radius.
- (2) Further, the blade 8c has the flat surface Qs to generate a negative pressure.
Therefore, the flow reattaches even when the flow is about to separate at the inner
peripheral curved surface Bs2.
- (3) Further, the blade thickness t is larger on the impeller inner peripheral side
than on the impeller outer peripheral side, and hence the distance between the adjacent
blades 8c is reduced.
- (4) Further, the flat surface Qs is flat. Therefore, unlike the case of a curved surface,
the blade thickness t does not abruptly increase as approaching toward the impeller
outer periphery, and hence the frictional resistance can be suppressed.
- (5) The pressure surface 13a of the blade 8c is also formed of the multiple arcs and
the straight portion (flat surface) in the range from the outer peripheral side toward
the inner peripheral side of the impeller. Thus, when air flows from the outer peripheral
curved surface Bp1 toward the inner peripheral curved surface Bp2 having a different
arc radius, the flow gradually accelerates to generate a pressure gradient on the
suction surface 13b. Therefore, the separation is suppressed and no abnormal fluid
noise is generated.
- (6) Further, the flat surface Qp on the downstream side is a tangent to the inner
peripheral curved surface Bs2. In other words, the blade 8c has the flat surface Qp
on the downstream side, and hence the blade 8c is shaped so as to be bent by a predetermined
angle with respect to the rotational direction RO. Therefore, unlike the case where
the straight surface (flat surface Qp) is absent, the flow can be directed toward
the suction surface 13b even when the blade thickness t2 of the inner peripheral end
portion 15b is large. Thus, the wake vortex can be suppressed when air flows into
the impeller from the inner peripheral end portion 15b.
- (7) The blade 8c has the thick inner peripheral end portion 15b. Thus, separation
is less liable to occur in various inflow directions in the outlet-side air duct E2.
- (8) Further, the blade 8c has the maximum thickness in the vicinity of the center
of the blade chord, which is positioned on the downstream side of the flat surface
Qs. Therefore, when the flow is about to separate after passing along the flat surface
Qs, the air flows along the inner peripheral curved surface Bs2 because the blade
thickness t is gradually increased toward the vicinity of the center of the blade
chord, which can suppress the separation.
- (9) Further, the blade 8c has the inner peripheral curved surface Bs1 having a different
arc radius on the downstream side of the inner peripheral curved surface Bs2. Therefore,
the separation of the flow is suppressed, the effective outlet-side air duct from
the impeller can be increased, the outlet airflow velocity is reduced and equalized,
and the load torque applied to the blade surface can be reduced.
Further, according to this embodiment, advantageous effects are obtained over the
related-art configurations disclosed in Patent Literature 1 to Patent Literature 3.
First, in the configuration disclosed in Patent Literature 1, the blade becomes thinner
in accordance with the position in the impeller rotational axis direction. Further,
in the configuration disclosed in Patent Literature 2, the blade is formed into a
tapered shape in which the blade has a smaller outer diameter and a larger inner diameter
as the blade extends from the base on the blade ring side. Further, the blade tip
portion is inclined in the rotational axis direction, and the blade outer diameter
varies in the impeller longitudinal direction. Therefore, a flow directed from one
ring toward the other ring in the impeller rotational axis direction is generated.
Further, the space between the impeller and the stabilizer or the casing facing the
impeller is enlarged in the rotational axis direction to increase the leakage loss
of the flow, and the space varies in the impeller rotational axis direction to cause
a flow from a region having a narrow space to a region having a wide space, thus further
increasing the leakage loss. Further, the efficiency deterioration increases the motor
power consumption. Further, two components are necessary in the configuration disclosed
in Patent Literature 3. Further, the orientation of the blade inclination is alternately
changed for each impeller element. Thus, regions where the flow concentrates in the
vicinity of the ring and regions where the flow separates from the vicinity of the
ring are alternately formed on a ring basis, and the blowing-out airflow velocity
distribution varies from a sparse state to a dense state or vice versa at wide intervals
on a two-ring basis. When dust and the like are deposited on the filter installed
at the air inlet of the air conditioner to increase the pressure loss, the sparseness
and denseness become significant to cause back flow in a wide sparse region in the
worst case. Therefore, high-humidity air flows back during the cooling, which may
cause dew condensation to discharge dew condensation water to the outside.
- (10) In connection with those problems, according to this embodiment, the blade 8c
is formed so that the inter-blade-ring center portions are retreated (or advanced)
in the impeller rotational direction in the impeller rotational direction while the
blade cross section orthogonal to the impeller rotational axis is the same. Thus,
the space between the impeller and the stabilizer 9 facing the impeller is the same,
and hence the flow leakage can be prevented from increasing due to a circular vortex
g1 caused by a difference in the space in the longitudinal direction, though this
increase of the flow leakage has been a problem in the above-mentioned related-art
configuration. Accordingly, the power consumption of the motor to be driven can be
reduced while achieving high efficiency.
- (11) Further, the blade is retreated in the impeller rotational direction and each
blade tip portion has a region that is inclined with respect to the impeller rotational
axis. Therefore, when the blade passes in the vicinity of the stabilizer 9 facing
the impeller, the flow is dispersed in the entire region of each blade tip portion
in the impeller longitudinal direction without pressure variations, thus reducing
harsh rotational noise (NZ noise) due to the number of rotations and the number of
blades . Accordingly, the noise can be reduced. As a result, the separation of the
flow from the blade surface can be suppressed on the inlet side and the outlet side
of the impeller. Therefore, the noise can be reduced, and further the power consumption
of the fan motor can be reduced. In other words, an indoor unit 100 having a quiet
and energy-saving cross-flow fan 8 mounted thereon can be obtained.
Second Embodiment
[0045] Next, a second embodiment of the present invention is described with reference to
FIG. 9 and FIG. 10. FIG. 9 and FIG. 10 are views for illustrating the second embodiment
of the present invention in the same manner as in FIG. 3 and FIG. 5, respectively.
The configuration in the second embodiment is the same as that in the above-mentioned
first embodiment except for portions to be described below.
[0046] In short, the second embodiment has an inverse relationship with the above-mentioned
first embodiment in the above-mentioned form indicated by the V-shape. According to
the second embodiment, each of a plurality of blades 108c is constructed to have such
a shape that the inner peripheral end portion 15b is retreated again in the rotational
direction after being advanced in the rotational direction from one corresponding
ring toward the other corresponding ring, and the outer peripheral end portion 15a
is also retreated again in the rotational direction after being advanced in the rotational
direction from one corresponding ring toward the other corresponding ring. In other
words, when the pressure surface of the blade 8c is viewed in a projective manner,
the inner peripheral end portion 15b and the outer peripheral end portion 15a in each
of the plurality of blades 8c have V-shapes, respectively. Therefore, each of the
inner peripheral end portion 15b and the outer peripheral end portion 15a is advanced
most in the rotational direction at the center portion between the pair of rings in
the rotational axis direction and is retreated more in the rotational direction at
portions on both sides of the center portion as approaching to the rings.
[0047] The second embodiment configured as described above can also achieve the same functions
as in the first embodiment regarding the air flow. In other words, in each of the
plurality of blades 108c, in a case where air is sucked to the inside from the outside
of the cross-flow fan 8, when flowing over the outer peripheral end portion 15a, the
air is accompanied by a blade tip vortex with the outer peripheral end portion 15a
as an end portion and flows along the blade 108c as a flow with suppressed separation,
thereby allowing a uniform flow to be maintained in a promotive manner. In a case
where air is blown out to the outside from the inside of the cross-flow fan 8, the
air flowing out from the outer peripheral end portion 15a toward the outside of the
cross-flow fan 8 flows so as to diffuse toward a corresponding pair of rings 8b, and
the flow can also be positively distributed to the vicinities of the pair of rings
to achieve a uniform flow between the pair of rings.
Third Embodiment
[0048] Next, a third embodiment of the present invention is described with reference to
FIG. 11, FIG. 12, and FIG. 13. FIG. 11, FIG. 12, and FIG. 13 are views for illustrating
the third embodiment of the present invention in the same manner as in FIG. 3, FIG.
4, and FIG. 5, respectively. The configuration in the third embodiment is the same
as that in the above-mentioned first embodiment except for portions to be described
below.
[0049] In short, each blade according to the third embodiment has the same form as in the
above-mentioned first embodiment as indicated by the V-shape, and further, portions
of each blade in the vicinities of a corresponding pair of rings (ring-side portions)
extend along the rotational axis direction (are not advanced or retreated in the rotational
direction). In other words, as illustrated best in FIG. 12, each of a plurality of
blades 208c has ring-side portions 220 at portions in a predetermined range from the
rings as portions in the vicinities of the corresponding pair of rings. The ring-side
portions 220 extend along the rotational axis direction without being advanced or
retreated in the rotational direction.
[0050] The third embodiment configured as described above can also achieve the same functions
as in the first embodiment regarding the air flow. Further, according to the third
embodiment, each of the plurality of blades achieves the following advantages due
to the pair of ring-side portions that extend along the rotational axis direction
without being advanced or retreated in the rotational direction. In other words, when
the plurality of impeller elements are stacked together and blades of one impeller
element are welded to the ring of another stacked impeller element, the blade tips
are upright and hence come into contact with the ring surface in an upright state.
Accordingly, the weldability is improved while achieving good assembling workability.
Further, the blade parallel portions (ring-side portions) at both ends have no inclination
to suppress concentration or dispersion of the flow on or from the ring surface, thus
stabilizing the flow in the vicinity of the ring. In this way, a uniform airflow velocity
distribution can be achieved and back flow can be prevented from occurring even when
dust and the like are deposited on the filter installed at the air inlet of the air
conditioner to increase the pressure loss. Therefore, a high-quality air conditioner
causing no dew condensation also during the cooling can be obtained.
[0051] Although the third embodiment is described above in an illustrative manner as a combination
with the first embodiment, the third embodiment may also be carried out in combination
with the second embodiment. In other words, the above-mentioned second embodiment
may be carried out so that the ring-side portions 220 extending along the rotational
axis direction without being advanced or retreated in the rotational direction are
formed in each blade 108c at portions in the vicinities of the corresponding pair
of rings.
Fourth Embodiment
[0052] Next, a fourth embodiment of the present invention is described with reference to
FIG. 14. FIG. 14 is a view for illustrating the third embodiment of the present invention
in the same manner as in FIG. 4. The configuration in the fourth embodiment is the
same as that in the above-mentioned first embodiment except for portions to be described
below.
[0053] In the above-mentioned first to third embodiments, the mode set so that each of the
inner peripheral end portion and the outer peripheral end portion in each of the plurality
of blades is advanced again in the rotational direction after being retreated in the
rotational direction, or the mode set so that each of the inner peripheral end portion
and the outer peripheral end portion in each of the plurality of blades is advanced
again in the rotational direction after being retreated in the rotational direction
is applied. However, the present invention is not limited thereto, but those modes
set as described above may be applied to one or both of the inner peripheral end portion
and the outer peripheral end portion at a plurality of portions. An example of the
fourth embodiment as described above is illustrated in FIG. 14.
[0054] In a blade 308c of FIG. 14 as an example of the fourth embodiment, a mode set so
that the inner peripheral end portion 15b is advanced again in the rotational direction
after being retreated in the rotational direction is applied at only one portion.
In other words, the inner peripheral end portion 15b is formed in the same manner
as the inner peripheral end portion of each blade according to the first embodiment.
On the other hand, in the outer peripheral end portion 15a of each blade 308c, the
modes set as described above are applied at a plurality of portions. In each of the
blade illustrated in the fourth embodiment and the blades illustrated in the above-mentioned
first to third embodiments, both sides of the blade with respect to its center between
the pair of rings in the rotational axis direction are constructed to have a symmetric
form.
[0055] Also in the fourth embodiment as described above, the same functions and effects
as in the above-mentioned first to third embodiments are obtained in each of corresponding
portions in the inner peripheral end portion and the outer peripheral end portion
of each blade.
[0056] In the description of the example illustrated in the fourth embodiment, the feature
of the fourth embodiment is applied to the blade having the inverted V-shape according
to the first embodiment. However, the fourth embodiment may also be carried out by
applying the feature of the fourth embodiment to the V-shaped blade according to the
second embodiment.
[0057] The details of the present invention have been described above specifically with
reference to the preferred embodiments, but it is apparent that a person skilled in
the art may employ various modifications based on the basic technical thoughts and
teachings of the present invention.
Reference Signs List
[0058] 1 main body, 8 cross-flow fan, 8a impeller, 8b ring (support plate), 8c, 108c, 208c,
308c blade, 9 stabilizer, 15a outer peripheral end portion, 15b inner peripheral end
portion, 100 air conditioner